PHOENIX - The Arizona Diamondbacks are in first place in the National League West, but …

The back end of their bullpen is a mess. Manager Kirk Gibson doesn't know who his closer will be day to day, and there's little reason to believe the in-house candidates will ease his anxiety.

They're 2 1/2 games ahead of the Los Angeles Dodgers, but …

The starting rotation is a 1,000-piece puzzle box with only two corner pieces: Left-handers Patrick Corbin and Wade Miley. Ian Kennedy has the second-worst ERA among National League starters, Brandon McCarthy and Trevor Cahill are on the disabled list, Tyler Skaggs is 22 and still trying to figure things out, and Randall Delgado likely is headed to the bullpen.

They've hung in there despite their liabilities, but …

Can they hold off the Dodgers without making a major deal before the July 31 trading deadline?

It's no surprise, then, that Arizona has been swept up in the trade rumor storm. Pick a website, any website, and you'll find the Diamondbacks linked to Matt Garza or Jake Peavy or Miami Marlins reliever Steve Cishek. If you think it's crazy now, just wait: The rumors will only intensify as the deadline approaches.

But here's something to keep in mind: Just because the Diamondbacks need to make a deal doesn't mean they should make a deal.

A few weeks ago, as he discussed the trading deadline, general manager Kevin Towers said it's important to have an honest assessment of your team. Do that, he said, and it's less likely you'll make a trade you regret for months, if not years.

OK, let's take his advice. The Diamondbacks are five games above .500. If they were in the American League East they'd be in fifth place; in the AL Central and West third place. They have the fifth-best winning percentage in the NL and their run-differential of plus-nine is by the far the lowest of any division leader.

In one sense the team's inadequacies are a credit to Gibson and the players. They've won despite their problems. But they also reveal just how fragile of a hold the Diamondbacks have. And that reality, more than anything, should guide Towers' thinking the next two weeks.

If an elite starter would put Arizona over the top in the NL West and, more importantly, give it a great shot of playing in the World Series, trading for a rental player like Garza would make sense. Opportunities like that don't come around very often; just ask the Washington Nationals, who forfeited their chance last year in order to protect Stephen Strasburg's arm and are one game over .500 this season.

But is Garza, who will become a free agent after the season, really worth two top minor-leaguers if all he does is help the Diamondbacks make up some ground on the Dodgers' rotation?

The same goes for the 32-year-old Peavy, who is due $14.5 million in 2014 and has made just 11 starts this season because of a rib injury. Is he the arm that gets Arizona to the World Series? If not, why pay the price?

As hard as it is for fans to accept, sometimes the best thing to do is nothing. Arizona's rotation next season likely will consist, in part, of Corbin, Miley, Skaggs and right-hander Archie Bradley, just named the top pitching prospect in the game by Baseball America.

Now, if Towers can swing a deal that helps this year's club without sacrificing too much of the future, by all means, do so. The division title is at stake; that's not something to forget.

But any major trade has to be scrutinized with a simple question: Will it give the Diamondbacks a legitimate chance to play in the World Series?

They're in first place, but…

Is this really the year?


• What: D-backs at Giants

• When: 7:15 p.m.

• TV; radio: FSAZ; 1490-AM